This invention relates to a polar wet pellet electrolytic capacitor method, and more particularly to a method of assembling the cathode of a wet pellet-type polar electrolytic capacitor.
In polar electrolytic capacitors the voltage is typically applied to the film-formed anode so that this is customarily termed the forward voltage. It is desirable, however, to provide the polar electrolytic capacitor with an ability to withstand at least a low voltage applied to the cathode, which is termed a reverse voltage. In order to possess this reverse voltage capability the cathode element of the capacitor must also have on its surface a dielectric film, and accordingly consists of a valve-metal.
Further the prime purpose of a capacitor is to provide capacitance, which in turn is directly related to cathode surface area. Therefore it is important to obtain in a wet polar electrolytic capacitor both an ability to withstand a reverse voltage and also a capacitor surface area capable of providing adequate capacitance.
It has been proposed to provide in a capacitor such as described above, a porous cathode in the capacitor can in the closed end of the can by inserting tantalum particles into the can and, when thus positioned within the can, sintering the particles to each other and to the can. This technique, among other disadvantages, necessitates the heating of the can. This leads to such shortcomings as the possible embrittlement of the metal can and the costly consumption of space and energy in a vacuum sintering furnace.
It is an object of this invention to provide a method that overcomes these and other related disadvantages of the prior art.
It is another object of this invention to provide a method for producing a polar wet electrolytic capacitor having a reverse voltage capability and high capacitance.
Still another object of this invention is the production of an increased capacitor surface carrying a dielectric for a polar wet electrolytic capacitor without subjecting the capacitor can to deleterious heat.